The research proposed herein is basically aimed at gaining a better understanding of differences which exist between plasma membranes of malignant and normal cells, and possible mechanisms by which these differences may contribute to the state of unregulated growth. One portion of the project will attempt to define a quantitative relationship between malignancy and two procoagulants, tissue factor and factor VII. Purified tissue factor and factor VII, which bind specifically to each other, and antibodies against these two molecules will be used to examine the occurrence and significance of altered tissue factor activity on the surface of malignant human cells. In another portion of the proposed work we seek to probe biochemical differences, between plasma membranes from malignant and normal cells, which are not related to the process of coagulation. This work, based upon ongoing research, will explore reactions between purified serum components and cell surface binding sites for these serum components which influence the migration of surface components along the plasma membrane, concanavalin A induced cell agglutination, and properties of growth control. Also novel moieties on the malignant cell surface, which bind specific serum proteins, will be used, after purification, to produce antibodies. These antibodies will, in turn, be used to examine their effects both in vitro and in vivo on the growth of tumor cells and implanted syngeneic tumors respectively.